CloseDepartment of Computer Science, Science and Technology, Aarhus University

DOI:

10.1007/978-3-642-42045-0_6

Abstract:

We present a constant-round unconditional black-box compiler that transforms any ideal (i.e., statistically-hiding and statistically-binding) straight-line extractable commitment scheme, into an extractable and equivocal commitment scheme, therefore yielding to UC-security [9]. We exemplify the usefulness of our compiler by providing two (constant-round) instantiations of ideal straight-line extractable commitment based on (malicious) PUFs [36] and stateless tamper-proof hardware tokens [26], therefore achieving the first unconditionally UC-secure commitment with malicious PUFs and stateless tokens, respectively. Our constructions are secure for adversaries creating arbitrarily malicious stateful PUFs/tokens. Previous results with malicious PUFs used either computational assumptions to achieve UC-secure commitments or were unconditionally secure but only in the indistinguishability sense [36]. Similarly, with stateless tokens, UC-secure commitments are known only under computational assumptions [13,24,15], while the (not UC) unconditional commitment scheme of [23] is secure only in a weaker model in which the adversary is not allowed to create stateful tokens. Besides allowing us to prove feasibility of unconditional UC-security with (malicious) PUFs and stateless tokens, our compiler can be instantiated with any ideal straight-line extractable commitment scheme, thus allowing the use of various setup assumptions which may better fit the application or the technology available.

ISBN:

9783642420450, 9783642420443

Type:

Conference paper

Language:

English

Published in:

Lecture Notes in Computer Science: 19th International Conference on the Theory and Application of Cryptology and Information Security, Bengaluru, India, December 1-5, 2013, Proceedings, Part II, 2013, p. 100-119